Implantable telemetry has progressed substantially over the past decade, with innovative devices being developed for monitoring heart rate, blood pressure, and other key functions in laboratory animals. These devices have allowed researchers to make great strides toward more-humane animal testing, reduced animal use, and improved efficiency and research quality. To date, however, one important aspect of cardiovascular monitoring has not been addressed: blood flow. In this project, the feasibility of a complete system for telemetric monitoring of blood pressure, ECG, and blood flow in conscious, freely moving animals larger than about 3 kg will be evaluated. The system will consist of novel, battery-powered implantable devices, receivers to pick up the telemetered signal; and a data-acquisition system to collect, store, and analyze the data. Key to success of this effort is to establish the feasibility of a novel approach to power reduction that, according to pilot evaluations, appears to be capable of reducing current drain by a factor of 15 or more over the best designs currently available. Phase 1 success will lead to a Phase II project designed to produce a prototype system. We believe that further improvements upon the Phase II design will make this technology viable in the much larger human clinical market. PROPOSED COMMERCIAL APPLICATIONS: Successful completion will result in a valuable new tool for biomedical researchers. In addition, the technology developed here has significant potential for human use once performance is improved in later generation designs.